Die Nationalmannschaft kicked off their World Cup campaign in style on Monday with a 4-0 Group G victory over Portugal.

However, some of the gloss has been taken off the win with news that Hummels -- scorer of his side's second goal -- is a doubt for the Ghana clash after bruising his right thigh.

The German Football Association (DFB) is not yet sure as to when exactly the Borussia Dortmund defender will be able to return to training or if he will be fit for Saturday's game.

Boateng, meanwhile, hurt the thumb on his right hand while in action on Monday, although the injury will not disrupt the Bayern Munich man's participation in the tournament as long as he wears a splint for the remaining matches.

The DFB released an official statement on Tuesday which read: "Hummels has suffered a bruise in his right thigh with bleeding into the muscles. When the Dortmund central defender can start training fully again and if he can play on Saturday in the second group match against Ghana in Fortaleza depends on the further course of healing."

The statement added: "The scan revealed that Boateng was hurt in the first World Cup group game against Portugal in Salvador during a fall, suffering a partial demolition of the sideband of the thumb of the right hand. The Munich defender has to wear a splint for six weeks, with which he can play with the accordance of the referee."